Fig. 4From: Efficacy of high-flow nasal cannula in patients with acute heart failure: a systematic review and meta-analysisComparison of PaCO2 and SpO2 (%). a High-flow nasal cannula oxygen (HFNC) versus conventional oxygen therapy (COT). b HFNC versus noninvasive ventilation (NIV). c Comparison of SpO2 (%) in patients who received HFNC compared to COT. CI confidence interval, IV Inverse varianceBack to article page